Method for removing kidney stones

ABSTRACT

A method for removing a kidney stone from a ureter may involve: advancing a distal end of an elongate, flexible kidney stone removal device into the ureter to a location near the kidney stone; advancing an expandable stone retention member out of an inner shaft of the device; visualizing at least part of the stone retention member with a camera disposed coaxially within the stone retention member; trapping the kidney stone in the stone retention member; surrounding at least a portion of the stone retention member and the trapped kidney stone with a wall protection member on the distal end of the kidney stone removal device; and removing the kidney stone removal device from the ureter while the stone retention member and the kidney stone are at least partially surrounded by the wall protection member.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. patent application Ser. No.14/205,217, entitled METHOD FOR REMOVING KIDNEY STONES, filed Mar. 11,2014, which claims priority to U.S. Provisional Patent Application Ser.Nos.: 61/812,511, entitled “Removal of Kidney Stones withoutFragmentation,” filed Apr. 16, 2013; 61/860,140, entitled “Devices andMethods for Removing Obstructions without Fragmentation,” filed Jul. 30,2013; and 61/897,769, entitled “Devices and Methods for RemovingObstructions without Fragmentation,” filed Oct. 30, 2013. The fulldisclosures of all of the above-listed patent applications are herebyincorporated by reference herein.

FIELD OF THE INVENTION

The present disclosure relates to medical devices and methods. Morespecifically, the disclosure relates to devices and methods for removingkidney stones.

BACKGROUND

Kidney stones (known as ureteral calculi in medical terminology) are asignificant burden on society and the health care system. Kidney stonesform in the body when the amount of various minerals in urine exceeds anamount that can be eliminated (the metastable limit), and the excessminerals form a precipitate. Most kidney stones are comprised of calciumand oxalate, though uric acid, struvite, cysteine, and other stonecompositions are also commonly found.

Kidney stones typically form in the parts of the kidney known as therenal pelvis or calyces and can stay there for years. When a stonedislodges, it makes its way down the upper urinary tract towards thebladder. Stones often get stuck en route to the bladder in the ureter.One reason for this is that mechanical rubbing of the sharp stone on theureter's mucosal lining causes an inflammatory response and swelling (or“edema”), which inhibits the stone's ability to pass. This obstructionimpedes the passage of urine from the kidney to the bladder, whichresults in increased internal pressure in the kidney. This pressure risecauses nerve fibers in the kidney to stretch, which in turn results inthe excruciating pain well known to accompany stones. Clinically, thispain is known as “renal colic” and comes in unexpected bursts lasting2-18 hours, until the internal pressure of the kidney is reduced. Aslong as the stone remains in the urinary tract, a patient will be atrisk for renal colic. Female patients describe stones as worse thannatural childbirth, while male patients describe it as the mostexcruciating experience of their lives. The pain associated with kidneystones is not correlated with stone size. In fact, several urologistsnote that often the smaller stones are the ones that hurt the most,prompting the quotation, “Stones are like puppies, the smaller ones makethe most noise.”

Pain relief from kidney stones typically occurs instantly after stonepassage or removal. Waiting for kidney stones to pass, however, can be along and painful process. Currently, three general types of kidney stoneremoval methods are used, all of which have at least some shortcomings.

Extracorporeal Shockwave Lithotripsy (ESWL) is a procedure in whichshockwaves are transmitted through the body in the direction of a kidneystone, in an attempt to fragment the stone into smaller pieces. For theESWL procedure, a patient lies on a special bed (which costsapproximately $750,000), is given sedation anesthesia, and is bombardedwith 45-90 shocks per minute over the course of 45 minutes to one hour.The shocks are so intense that they must be synchronized with thepatient's heartbeat so as not to cause cardiac arrhythmias. ESWLoutcomes are mixed: 33% of patients have a successful outcome and pass“sand,” 33% of patients pass several smaller stones with excruciatingpain, and 33% of patients are unaffected by the treatment. Recentstudies have raised concerns about potential long-term complications ofESWL, including hypertension and diabetes. Due to the uncertainoutcomes, required sedation anesthesia, and potentially hazardousmechanism of the treatment, ESWL is indicated only for patients with8-13 mm stones located in the kidney itself. Generally, stones of thissize and location are asymptomatic.

Ureteroscopy (URS) is a procedure in which a urologist inserts anendoscope up the urethra, into the bladder, and up the ureter to thesite of the stone. Using a laser, the urologist fragments the stone intosmaller pieces and retracts the fragments with a basket. The procedurerequires general anesthesia, high skill level from the urologist, andanywhere from 20 minutes to one hour. The endoscope, laser source, andfluoroscopy require an investment of approximately $225,000 in capitalequipment alone. The ureteroscopes themselves cost approximately $15,000and can typically be used in only about 15 procedures before needing tobe replaced or repaired. The typical amount of manipulation of theureteroscope within the ureter during the procedure, as well as theoverall time spent in the ureter, can induce ureteral stricture(blockages of the ureter caused by a process similar to scarring). Theprocedure outcome is generally highly effective, but due to the risk ofcomplications and required general anesthesia, URS is generallyrecommended only for stones that are 8-15 mm in size.

Percutaneous Nephrectomy Lithotripsy (PCNL) is a surgical procedure inwhich a tube is inserted through the back into the kidney. Stones areremoved through the tube, using lasers, graspers, and aspiration. ThoughPCNL is highly effective, its invasiveness renders it applicable only tostones larger than 15 mm.

As described above, the currently available procedures for kidney stoneremoval are generally quite invasive and require (1) at least sedationanesthesia and in many cases general anesthesia, (2) expansive,specialized capital equipment, and (3) experienced and knowledgeableurologists to perform the procedures. Furthermore, most small kidneystones ultimately pass without any intervention. Therefore, despite theincredible, debilitating pain involved in passing kidney stonesnaturally, that is typically the method of choice, since kidney stoneremoval methods have such significant drawbacks.

Thus, it would be advantageous to have additional treatment options forkidney stone removal. Ideally, these options would be less invasive,less expensive, less prone to side effects, and/or require lessphysician expertise to perform. It would also be ideal if some of theadditional treatment options could be used, or adapted for use, in otherparts of the body to remove other obstructions. At least some of theseobjectives will be met by the embodiments described herein.

BRIEF SUMMARY

This application describes a number of embodiments of devices, systemsand methods for removing obstructions from body lumens and passageways.Although the embodiments are described primarily for use in removingkidney stones from the urinary tract, at least some of the embodimentsmay also be used, or may be adapted for use, in other parts of the bodyto remove other obstructions. Therefore, the following descriptionshould not be interpreted as limiting the scope of this application tokidney stone removal, since any embodiment described may be used oradapted for other uses. The terms “kidney stone,” “stone” and“obstruction” may be used interchangeably herein. Additionally, althoughmany of the descriptions below focus on removal of a kidney stone fromthe ureter, other parts of the body and/or other obstructions may beaddressed in other embodiments. The terms “lumen” and “vessel,” forexample, may be used generally and interchangeably to refer to areas inwhich obstructions may be located.

Generally, this application describes devices, systems and methods forremoving kidney stones from ureters (or other obstructions from otherbody lumens). In some embodiments, kidney stone removal may be performedwithout fragmenting the stones before removal. Alternatively, someembodiments may be used to remove fragmented stones. The variousembodiments of devices, systems and methods described herein typicallyinclude one or more elongate, flexible shafts, arranged coaxiallyrelative to one another, one or more end effectors at the distal end ofthe shaft(s) for removing the kidney stone, and a handle at the proximalend of the shaft(s) for manipulating the shaft(s) and end effector(s).The inventors of the devices, systems and methods described herein havefound that it may be advantageous to include, in each embodiment, atleast two of the following three aspects. It may be most advantageous toinclude all three aspects in a given embodiment, and some embodiments doinclude all three, but that is not a requirement.

Obstruction retention. This refers to a mechanism for retaining orotherwise applying a force to the kidney stone or other obstruction forthe purpose of retaining, manipulating and eventually removing theobstruction. Several examples of obstruction retention members describedbelow include, but are not limited to, expandable graspers, expandablebaskets and expandable balloons with cavities for trapping obstructions.

Ureter wall protection. This refers to a mechanism for protecting theureteral wall (or wall of another lumen or vessel) from trauma caused bythe stone or other obstruction rubbing against the wall during removal.In some but not all embodiments, ureter/vessel wall protection mayinvolve ureteral/vessel dilation. Such embodiments may include amechanism to provide dilation around the obstruction to reduce frictionand eliminate trauma to the lumen wall caused by contact of theobstruction surface with the lumen wall. Generally, embodiments mayinvolve any soft, compliant or low-friction material that may bepositioned between the stone and the ureter wall. Several examples ofureter wall protection members described below include, but are notlimited to, expandable balloons, shafts, and hydrodilation members thatemit fluid to expand the ureter/vessel/lumen.

Obstruction detection and/or identification. This refers to a mechanismto identify the obstruction location and ensure retention and/ordilation is applied in the proper location relative to the obstruction.Detection may also be used to ensure removal of the stone and forgeneral navigational purposes in the lumen or other orifice. One exampleof an obstruction detection member described below includes, but is notlimited to, a fiber optic camera incorporated into an obstructionremoval device.

Many of the embodiments of devices, systems and methods described belowmay include one mechanism from each of the three categoriesabove—obstruction retention, ureter wall protection and obstructiondetection. This combination may be advantageous in providing foreffective kidney stone removal with minimal trauma to the ureter. Inmany embodiments, it will be possible to combine different mechanismsfrom one category with different mechanisms from another category toform an alternative embodiment. For clarity, the descriptions below willnot always repeat details about various mechanisms from each categoryfor each embodiment. For example, if a fiber optic camera is describedin relation to one embodiment as a stone detection mechanism, that samecamera need not be described again in detail for use with anotherembodiment. Mechanisms from each of the three categories may be combinedwith each other in any suitable way to form various alternativeembodiments.

In one aspect, a system for removing a kidney stone from a ureter mayinclude: an elongate, flexible, outer shaft, having a distal endconfigured to be advanced into the ureter and a proximal end; anelongate, flexible, inner shaft extending through at least part of theouter shaft, where at least one of the outer shaft or the inner shaft ismoveable along a longitudinal axis relative to the other shaft; anexpandable stone retention member extending through at least part of theinner shaft and moveable along the longitudinal axis relative to theinner shaft, where the stone retention member includes a retentionmember shaft and a stone retention portion disposed at a distal end ofthe retention member shaft; an elongate, flexible camera positionedcoaxially within the retention member shaft, such that a distal end ofthe camera is located at or near a distal end of the inner shaft; and ahandle coupled with the proximal end of the outer shaft, a proximal endof the inner shaft, and a proximal end of the retention member shaft.The handle may include a shaft actuator for moving the inner shaftrelative to the outer shaft and/or the outer shaft relative to the innershaft and a retention member actuator for advancing the stone retentionmember out of the distal end of the inner shaft.

Some embodiments may further include a compliant ureter wall protectionmember attached to the outer shaft at or near its distal end. Suchembodiments may also optionally include a wall protection member shaftdisposed between the outer shaft and the inner shaft, where a first endof the wall protection member is coupled with the distal end of theouter shaft, and a second end of the wall protection member is coupledwith a distal end of the wall protection member shaft. In oneembodiment, the wall protection member may be an inflatable balloon, anda space between the outer shaft and the wall protection member shaft mayact as an inflation lumen in fluid communication with the balloon. Insuch embodiments, the handle may further include a balloon inflationport in fluid communication with the inflation lumen. In one embodiment,the balloon may be configured to at least partially deflateautomatically when the stone retention member and a retained stone arepulled into the balloon. In one embodiment, the balloon inflation portmay be configured to attach to a syringe, and automatic deflation of theballoon may cause a plunger of the syringe to automatically retract.

In some embodiments, the balloon may have a proximal taper with a firsttaper angle and a distal taper with a second taper angle that is greaterthan the first taper angle. Optionally, the wall protection member shaftmay be movable along the longitudinal axis relative to the outer shaft,such that sliding the wall protection member proximally relative to theouter shaft causes the wall protection member to invaginate. In someembodiments, the system may further include a wall protection membershaft actuator on the handle.

Optionally, the handle may further include a handle extension, which isa portion of the handle that slides in and out of the distal end of themain portion of the handle—e.g., the larger, more proximal portion. Sucha handle extension may be attached to any one or more components of thesystem, so that as the extension slides in and out of the handle, theattached component(s) move with the extension. Alternatively oradditionally, the handle extension may include one or more otherfeatures. For example, the handle extension may be attached to aproximal end of an outer shaft of the system, and in some embodimentsthe distal end of the outer shaft may be attached to a wall protectionmember, such as an inflatable balloon. Moving the handle extension maythus move the outer shaft and change the configuration of the balloon.Examples of other features of a handle extension may include, but arenot limited to, an inflation fluid port and an irrigation fluid port.The handle extension is an optional feature and may be referred tosimply as a sliding handle piece or a moveable part of the handle. Invarious alternative embodiments, any feature(s) described as residing onthe handle extension may instead by housed on the more proximal, mainpart of the handle.

The system may also optionally include at least one irrigation fluidchannel and/or aperture in the inner shaft, in the wall protectionmember, in a space between the inner shaft and the retention membershaft, or in any other suitable location, for allowing passage ofirrigation fluid out of the system. In these embodiments, the handle mayfurther include an irrigation port. In one embodiment, for example, anirrigation port is in fluid communication with a space between the innershaft and the retention member shaft, and that space acts as anirrigation fluid channel. In one embodiment, the stone retention portionof the stone retention member may be an expandable basket. In variousembodiments, the camera may be a fiber optic camera, a CCD image sensor,a CMOS device or the like. The camera may optionally be removable fromthe system, in some embodiments. In some embodiments, the system mayalso include an inflation device attachable to the handle for inflatinga ureter wall protection balloon coupled with the outer shaft and anirrigation fluid delivery device attachable to the handle for providingirrigation fluid during removal of a kidney stone. In some embodiments,the inflation device may be a syringe. Optionally, the system mayfurther include a suction port on the handle for providing suction forcethrough at least one of the inner shaft or the retention member shaft.

In another aspect, a device for removing a kidney stone from a uretermay include: an elongate, flexible, outer shaft having a distal endconfigured to be advanced into the ureter and a proximal end; anelongate, flexible, inner shaft extending through at least part of theouter shaft, where at least one of the outer shaft or the inner shaft ismoveable along a longitudinal axis relative to the other shaft; anexpandable stone retention member extending through at least part of theinner shaft and moveable along the longitudinal axis relative to theinner shaft, where the stone retention member includes a retentionmember shaft having a distal end and stone retention portion disposed atits distal end, and where the retention member shaft forms a cameralumen configured to allow a flexible camera to be positioned coaxiallywithin it; and a handle coupled with the proximal end of the outershaft, a proximal end of the inner shaft, and a proximal end of theretention member shaft. The handle may include a shaft actuator formoving the inner shaft relative to the outer shaft and/or the outershaft relative to the inner shaft and a retention member actuator foradvancing the stone retention member out of the inner shaft distal end.

In some embodiments, the handle may further include a camera attachmentportion for attaching a proximal portion of the camera. Optionally, thedevice may further include a wall protection member coupled with thedistal end of the outer shaft. Such an embodiment may also include awall protection member shaft slidably disposed between the inner shaftand the outer shaft, where the wall protection member is attached at oneend to the distal end of the outer shaft and at an opposite end to adistal end of the wall protection member shaft. In some embodiments, thewall protection member may be an inflatable balloon, and a space betweenthe wall protection member shaft and the outer shaft may serve as aninflation lumen in fluid communication with the balloon. In suchembodiments, the handle may optionally further include a ballooninflation port in fluid communication with the inflation lumen.

The device may also include an irrigation fluid channel formed as aspace between the inner shaft and the retention member shaft. Such anembodiment may also include an irrigation fluid port on the handle influid communication with the irrigation channel. Although suction is notrequired in any embodiment, one optional feature of the device may be asuction port on the handle for providing suction force through the innershaft and/or the retention member shaft.

In another aspect, a method for removing a kidney stone from a uretermay involve: advancing a distal end of an elongate, flexible kidneystone removal device into the ureter to a location near the kidneystone; advancing an expandable stone retention member out of an innershaft of the device; visualizing at least part of the stone retentionmember with a camera disposed coaxially within the stone retentionmember; trapping the kidney stone in the stone retention member;surrounding at least a portion of the stone retention member and thetrapped kidney stone with a wall protection member on the distal end ofthe kidney stone removal device; and removing the kidney stone removaldevice from the ureter while the stone retention member and the kidneystone are at least partially surrounded by the wall protection member.

In some embodiments, the retention member may include a retention membershaft and a stone retention portion disposed at a distal end of theretention member shaft, and the camera may be disposed in the retentionmember shaft such that a distal end of the camera is located at or nearthe distal end of the inner shaft. In some embodiments, the surroundingstep may involve pulling the stone retention member and the trappedkidney stone proximally into the wall protection member. Alternatively,the surrounding step may involve advancing the wall protection memberaround at least part of the stone retention member and the trappedkidney stone.

In some embodiments, the wall protection member may be an inflatableballoon, and the method may further involve inflating the balloon. Insuch embodiments, surrounding at least part of the stone retentionmember and the trapped kidney stone may invaginate the balloon. In someembodiments, the surrounding step may automatically partially deflatethe balloon and thus cause a plunger of an inflation syringe used toinflate the balloon to retract. In some embodiments, the balloon may beinflated after trapping the kidney stone. The method may optionallyfurther include inflating the balloon at least one additional timeduring removal of the device from the ureter. Additionally, the methodmay also optionally include at least partially deflating the balloon atleast one time before or during removal of the device from the ureter.These inflations and deflations may be performed, for example, to dilatea stricture or narrowing of the ureter.

Another optional step of the method is passing irrigation fluid,lubrication fluid and/or anesthetic out of the kidney stone removaldevice in an area near the kidney stone. In some cases, one fluid may beused for multiple purposes, such as irrigation to maintain a clear fieldof view for the camera, lubrication for facilitation stone removal,and/or anesthesia for reducing pain. A solution including lidocaine, forexample, may achieve these purposes. In some embodiments, the method mayalso involve applying suction force through the device to help retainthe kidney stone within the device. However, application of suction isnot required as part of the method. Removing the camera from the deviceafter use is yet another optional step. In some embodiments, the cameramay be reusable for multiple kidney stone removal procedures. In suchcases, the camera will be sterilizable by at least one sterilizationmethod.

The method may also include, before the trapping step, advancing theinner shaft around the kidney stone and advancing an expandable, stoneretention portion of the stone retention member out of the inner shaft.In one embodiment, trapping the stone comprises pulling back the stoneretention member to trap the stone in the stone retention portion. Insome embodiments, the surrounding step may involve pulling back theinner shaft to thus pull back the retained stone and the stone retentionportion into the wall protection member. Any embodiments may furtherinvolve visualizing the trapping, surrounding and/or removing steps,using the camera.

These and other aspects and embodiments will be described in furtherdetail below, in reference to the attached drawing figures.

BRIEF DESCRIPTION OF DRAWINGS

Certain preferred embodiments and modifications thereof will becomeapparent to those skilled in the art from the detailed description belowhaving reference to the figures that follow.

FIGS. 1A and 1B are perspective and side views, respectively, of asystem for removing kidney stones from ureters or other obstructionsfrom other body lumens, according to one embodiment;

FIGS. 2A and 2B are perspective views of a distal portion of the systemof FIGS. 1A and 1B, illustrating a portion of a method for retaining akidney stone in the system, according to one embodiment;

FIGS. 3A and 3B are side cross-section and end-on cross-section views,respectively, of a kidney stone removal system similar to the system ofFIGS. 1A, 1B, 2A and 2B;

FIGS. 4A-4E are schematic side views of a ureter and kidney stone,illustrating a method for removing a stone from a ureter using a systemsuch as that described in FIGS. 1A, 1B, 2A, 2B, 3A and 3B, according toone embodiment;

FIGS. 5A-5F are schematic side views of a ureter and kidney stone,illustrating a method for removing a stone from a ureter using a systemsuch as that described in FIGS. 1A, 1B, 2A, 2B, 3A and 3B, according toan alternative embodiment;

FIGS. 6A and 6B are perspective views of a distal portion of a kidneystone removal system having an expandable basket and a funnel member,according to an alternative embodiment;

FIGS. 7A and 7B are perspective and close-up views, respectively, of anexpandable grasper that may be a part of a kidney stone removal system,according to an alternative embodiment;

FIGS. 8A and 8B are perspective views of a distal portion of a kidneystone removal system (FIG. 7B shown within a ureter with a kidney stone)having an expandable grasper and a compliant membrane, according to analternative embodiment;

FIG. 9 is a side view of a distal portion of a kidney stone removalsystem having an expandable grasper and an inflatable balloon, accordingto an alternative embodiment;

FIG. 10 is a perspective view of a distal portion of a kidney stoneremoval system having an expandable grasper, a compliant membrane and acamera, according to an alternative embodiment;

FIGS. 11A and 11B are side views of a distal portion of a kidney stoneremoval system having an expandable mesh basket and an inflatableballoon, according to an alternative embodiment;

FIG. 12 is a perspective view of a distal portion of a kidney stoneremoval system having an expandable mesh basket and a webbing betweenthe mesh, according to an alternative embodiment;

FIGS. 13A and 13B are perspective and side views, respectively, of adistal portion of a kidney stone removal system having a balloon,according to one embodiment;

FIG. 14A is a perspective view of a distal portion of a kidney stoneremoval system having a balloon, according to an alternative embodiment;and

FIG. 14B is a perspective view of a distal portion of a kidney stoneremoval system having a balloon, according to another alternativeembodiment.

DETAILED DESCRIPTION

The following description outlines various embodiments of devices,systems and methods for removing obstructions from body lumens, such askidney stones from ureters. Although the following descriptions focus onkidney stone removal applications, some or all of the aspects andembodiments described below may alternatively be used in other bodylumens for removal of other obstructions. As mentioned above, thevarious embodiments described herein typically include at least two andsometimes three of the following: an obstruction retention member, avessel/lumen wall protection member, and an obstruction detection and/oridentification member. Some descriptions below are directed to only oneor two of these components, while other descriptions relate toembodiments of devices, systems or methods including all threecomponents. Alternative embodiments, some of which may not be describedbelow, may include various alternative combinations of the componentsdescribed below in relation to other embodiments. In various alternativeembodiments, the devices, systems and methods may be altered, combinedor otherwise changed, without departing from the scope of the inventionas set forth in the claims.

Referring to FIGS. 1A-1B, in one embodiment, a kidney stone removalsystem 10 may include a handle 12, a handle extension 14, an outer shaft16 and an end effector 18. In one embodiment, end effector 18 mayinclude an expandable stone retention member 20 (also referred to inthis embodiment as “basket 20”), a visualization device 22 (alsoreferred to in this embodiment as “camera 22”), and a wall protectionmember 24 (also referred to in this embodiment as “inflatable balloon24”). Handle extension 14, as mentioned above, is simply a slidingportion of handle 12, which slides out of and back into the distal endof handle 12. It is an optional feature. In this embodiment, handleextension 14 is coupled with a balloon fill port 26, an irrigation port28 and a shaft slider 30. Handle 12 may include a retention memberslider 32 and may be coupled with a camera proximal portion 34, whichmay include an imaging sensor (and electronics) and/or a light source insome embodiments. Many of these features are described in further detailbelow.

In various embodiments, end effector 18 may include a number ofvariations, such as different components, differently sized components,and the like. For ease of description, end effector 18 is referred tohere as a distal portion of system 10, which includes multiple differentkidney stone removal components. Alternatively, the term “end effector”may be used elsewhere herein to refer to one component at or near thedistal end of system 10. In the embodiment illustrated in FIGS. 1A and1B, end effector 18 includes stone retention member 20, which includes aretention member shaft (not visible in FIGS. 1A and 1B) and anexpandable, stone retention portion extending distally from a distal endof the retention member shaft. In this embodiment, the stone retentionportion is an expandable basket. Again, the terms “stone retentionmember 20” and “basket 20” may be used interchangeably herein, althoughthe stone retention member may comprise a one-piece or attachedretention member shaft and expandable stone retention portion. Inalternative embodiments, the stone retention portion of stone retentionmember 20 may be something other than an expandable basket, such as anexpandable cup, tongs or the like.

Basket 20 may be made of Nitinol, spring stainless steel, shape memorypolymer, or any other suitable shape-memory material. Basket 20 may bean extension of (or alternatively attached to) a distal end of theretention member shaft, which may be disposed within an inner shaft (notvisible in FIGS. 1A and 1B). The inner shaft, in turn, is located withinouter shaft 16. The various relationships of the shafts, according to atleast one embodiment, are described in further detail below, in relationto FIGS. 3A and 3B. Generally, basket 20 is housed within the innershaft during advancement of shaft 16 into and through the ureter. Basket20 is then advanced distally out of the inner shaft to be released fromconstraint. Upon release from constraint, basket 20 expands and may thenbe used to trap a kidney stone. Basket 20 may include any suitablenumber of struts, such as but not limited to the four struts illustratedin FIGS. 1A and 1B.

In some embodiments, end effector 18 may also include visualizationdevice 22 (or “camera 22”) for detection and visualization of kidneystones. Visualization device 22 refers generally to the entire deviceused in system 10 for visualization and not just the distal tip ofdevice 22 that is illustrated in FIGS. 1A and 1B. For example, camera 22typically extends from a distal end, located at or near a distal end ofthe inner shaft, through the inner shaft, to camera proximal portion 34,which is attached to handle 12. Camera 22 may be any suitable smallcamera, such as but not limited to a fiber optic camera, a CCD(charge-coupled device) image sensor or a CMOS (complementarymetal-oxide-semiconductor) camera. Camera proximal portion 34 may beattached via a cable with one or more conductors to an image-processingconsole (not shown), which displays an image on a viewing screen.Alternatively, camera proximal portion 34 may contain an eyepiece,through which an image may be observed and/or magnified using othertechniques common in the art of endoscopy. The distal, viewing end ofcamera 22 is located in end effector 18, so that it may be used tovisualize a kidney stone located in the ureter in front of system 10. Insome embodiments, camera 22 is located coaxially within the retentionmember shaft (again, not shown in FIGS. 1A and 1B but illustratedlater), with its distal end positioned at or near a distal end of theinner shaft and/or the retention member shaft. The retention membershaft extends distally to form basket 20, and the distal tip of camera22, in these embodiments, generally faces directly into the expandableportion of basket 20.

In some embodiments, the distal end of camera 22 may be fixed in place,relative to the distal tip of the inner shaft. Camera 22 extends fromits distal end, proximally through the retention member shaft to cameraproximal portion 34, which is coupled with handle 12. In variousembodiments of system 10, any suitable camera 22 currently available oras yet to be invented may be used. Furthermore, although visualizationdevice 22 is referred to herein as a “camera,” any other suitablevisualization device may be used in alternative embodiments. In someembodiments, system 10 may include camera 22, while in otherembodiments, system 10 may be provided without camera 22, and any of anumber of available cameras may be added to system 10.

Finally, end effector 18 may also include wall protection member 24,also referred to as inflatable balloon 24, which is used both forprotecting the ureteral wall from trauma and also to aid in stoneretention. In alternative embodiments, some of which are describedbelow, wall protection member 24 may be something other than aninflatable balloon, such as a compliant cup or other form of compliantmaterial. Thus, use of the term “balloon” in describing the presentembodiment should not be interpreted as limiting. Balloon 24 may also beused to help maintain a position of system 10 relative to the ureter,once it is inflated. Additionally, balloon 24 may be used duringadvancement or withdrawal of system 10 into or out of the ureter, toexpand a portion of the ureter, for example to expand a constriction orother narrowing of the ureter. Balloon 24 may be made of any suitablepolymer, polymeric blend or other material or combination of materials.Generally, such material(s) will be relatively atraumatic to theureteral wall and ideally will have a low-friction and/or hydrophilicouter surface or coating that facilitates sliding along the wall. Insome embodiments, balloon 24 may be coated with a lubricious coatingand/or may include one or more small holes for allowing a lubricatingfluid to escape.

As will be described in further detail below, in one embodiment, endeffector 18 may be advanced through the ureter to a location near thekidney stone. The small, inner shaft, containing basket 20, may beextended out of outer shaft 16 during all, or at least part of, thisadvancement, and the whole device may be advanced until a distal end ofthe inner shaft is advanced beyond the stone. Basket 20 may then beadvanced out of the inner shaft to allow it to expand, and the wholedevice may be pulled back to capture the stone. Camera 22is coaxiallylocated within the retention member shaft (or “basket shaft”) and ispositioned with its distal end at or near a distal end of the innershaft and/or the retention member shaft, so that it faces into basket 20to help visualize the stone and the process of capturing the stone. Oncethe stone is trapped in basket 20, inflatable balloon 24 may beinflated, typically until it contacts the inner wall of the ureter.Basket 20 and stone may then be pulled back proximally into the distalend of balloon 24, such that balloon 24 invaginates to receive andenvelop at least part of basket 20 and stone. At this point, system 10may be withdrawn from the ureter, with balloon 24 helping to preventtrauma to the ureteral wall and reducing the amount of force required toremove the stone. In some embodiments, irrigation fluid for enhancingvisualization and/or lubrication may also be introduced into the ureterduring the method. Although suction may also be used in some embodimentsto help trap and/or retain the stone in basket 20, it is not a necessarycomponent of the system or method. This is only one embodiment of amethod for stone removal, and this embodiment and alternativeembodiments are described in further detail below.

In one embodiment, handle extension 14 slides at least partially intoand out of handle 12 to advance and retract one or more of the shafts ofsystem 10. Handle extension 14 is an optional feature, and inalternative embodiments it may be eliminated. Additionally, themovements of the various shafts of system 10 described herein areexemplary in nature and should not be interpreted as limiting. Someshafts move relative to other shafts, and some shafts may be fixedrelative to handle 12 or handle extension 14. For example, in oneembodiment, camera 22 may be fixed to handle 12, so that it does notmove during use of system 10, and instead, other parts move around it.This relationship may be advantageous, because it may reduce wear andtear on camera 22, which in some embodiments may be reusable. The innershaft, which again will be shown and described in greater detail below,may also be fixed to handle 12 in one embodiment, so that the innershaft covers most or all of the long, thin, flexible portion of camera22 at all times. In alternative embodiments, however, the variousrelative movements and relationships described herein may be changed,without significantly changing the overall function of system 10.Therefore, the descriptions of shaft movements, actuators, movement ofhandle extension 14 and the like should not be interpreted as limitingthe scope of the invention as it is described in the claims.

In one embodiment, handle extension 14 is fixedly attached to outershaft 16, such that handle extension 14 and outer shaft move together,relative to handle 12 and the inner shaft that houses basket 20. Handleextension 14 may slide in and out of handle 12 by manipulating shaftslider 30, which is fixedly attached to extension 14. Handle extension14 may also include balloon fill port 26, which may be coupled with asource of balloon inflation fluid, such as but not limited to salinesolution, water or contrast agent.

Handle extension 14 may also include irrigation port 28, which may becoupled with a source of irrigation fluid, such as but not limited tosaline solution, water or a solution including a pharmaceutical agent,such as lidocaine. The irrigation fluid may exit system 10 near thedistal (viewing) end of camera 22, for example out of a space betweenthe distal end of the inner shaft and the distal end of the retentionmember shaft, or alternatively, through one or more irrigation fluidapertures on the inner shaft, the wall retention member or the like.Irrigation fluid may be used, for example, to help enhance visualizationby keeping the distal end of the camera 22 clean and/or expanding acollapsed ureteral lumen, thus increasing the ability to visualize thelumen itself. Additionally, irrigation fluid may help to reduce frictionwhile removing the kidney stone, to reduce pain, for example whenlidocaine is used as lubricant, and/or for any combination of these orother purposes. In some embodiments, irrigation fluid may be passed outof the distal end aperture(s) or channel(s) at a low flow rate—forexample, less than 5 cc/min. This low flow rate might be lower, forexample, than flow rates typically used with currently availableendoscopes for irrigation.

In one alternative embodiment, irrigation port 28 and balloon fill port26 may be combined into a common port fluid infusion port. For example,in one embodiment, inflation fluid may also act as irrigation fluid byexiting out of the inflated balloon through one or more small apertures.Alternatively, fluid may enter the combined port and may then bedirected into a balloon inflation lumen and an irrigation fluid lumen.

Handle 12 couples with camera proximal portion 34 and also may includeretention member slider 32, which is attached to the proximal end of theretention member shaft. Retention member slider 32 may be used toadvance and/or retract basket 20 out of and/or into the inner shaft.Handle 12 also provides a portion of system 10 that a user mayconveniently grasp with one hand. Slider(s) 30 and/or 32 may bemanipulated with the same hand that holds handle 12 or with the oppositehand. Handle 12 and handle extension 14 may be made of metal, polymer, acombination of metal and polymer, or any other suitable material orcombination of materials. Outer shaft 16 may be made of any suitable,biocompatible, flexible polymer. In some embodiments, system 10 may befully disposable. In alternative embodiments, camera 22 may be reusable,and the rest of system 10 may be disposable. Finally, it may be possiblethat in some embodiments all of system 10 may be reusable andsterilizable, such as by autoclave or other sterilization processes.

In some embodiments, the proximal end of outer shaft 16 may removablyattach to the distal end of handle extension 14, for example by asnap-on fit in one embodiment. This snap-on configuration may have twoprimary advantages. First, outer shaft 16 may be attached to handle 12after shaft 16 has been advanced into the ureter through an endoscope(such as but not limited to a cystoscope or steerable shaft) to positionthe distal end of shaft 16 in a desired location for stone removal. Thisallows the physician user to remove the endoscope after positioning theouter shaft 16 and prior to operation, improving patient comfort andease of use. Second, handle 12 may be reusable, even if some or all ofthe rest of system 10 is disposable.

Referring now to FIGS. 2A and 2B, a distal portion of system 10 isillustrated in greater detail. In these figures, a kidney stone S isshown trapped inside basket 20. In some embodiments, balloon 24 may haveseveral distinct portions, such as a proximal attachment portion 35attached to outer shaft 16, a proximal tapered portion 36, a middleportion 37, a distal tapered portion 38 and a distal attachment portion39 attached to a wall protection member shaft 42. Generally, it may beadvantageous for proximal tapered portion 36 to have a more gradualtaper than distal tapered portion 38. For example, in some embodiments,proximal tapered portion 36 may have a taper angle of between about 5degrees and about 25 degrees, and ideally between about 10 degrees andabout 15, relative to a longitudinal axis of balloon 24. Distal taperedportion 38 may have a taper angle of between about 30 degrees and about90 degrees, and ideally between about 40 degrees and about 70 degrees,relative to the longitudinal axis of balloon 24. In one specificexample, distal tapered portion 38 may have a taper angle of about 45degrees, and proximal tapered portion 36 may have a taper angle of about10 degrees. The “steeper” taper angle of distal tapered portion 38relative to that of proximal tapered portion 36 will cause distaltapered portion 38 to preferentially collapse into balloon 24 (or“invaginate”) when basket 20 and stone S are pulled back into distaltapered portion 38, rather than having any proximal tapered portion 36collapse. Additionally, the steeper taper angle of distal taperedportion 36 may facilitate engulfing the stone with balloon 24 with lessrelative movement between outer shaft 16 and the inner balloon shaft.

FIG. 2B illustrates this preferential invagination of distal taperedportion 38. Although distal tapered portion 38 is not visible in FIG.2B, it has been pulled back into balloon 24 by basket 20 and stone S,which middle portion 37 and proximal tapered portion 36 remainrelatively in the same configuration. As basket 20 and stone S arepulled further into balloon 24, part of middle portion 24 may be made toinvaginate into the interior of balloon 24, and in this way all or partof stone S may be encircled by balloon 24. Basket 20 and stone S may bepulled proximately by sliding the retention member shaft (not visiblehere, because it is within wall protection member shaft 42 and the innershaft) proximally, for example via a slider on handle 12 or handleextension 14. Pulling basket 20 and stone S proximally into balloon 24may cause wall protection member shaft 42 to slide proximally as balloon24 invaginates. In some embodiments, distal attachment portion 39 andproximal attachment portion 35 may be of approximately equal lengths.Alternatively, they may have different lengths.

Balloon 24 may serve a number of different functions. For example,balloon 24 may reduce friction against the ureter wall by the trappedstone during removal, it may reduce trauma of the ureter wall by sharpedges of a trapped stone, and/or it may help retain the stone withinsystem 10 in general. The retaining function may occur if balloon 24surrounds the stone partially or completely and thus helps with thetrapping/retaining of the stone. In other words, balloon 24 and basket20 may work together to trap and retain the stone.

In some embodiments, as an alternative or in addition to havingdifferent taper angles, distal tapered portion 38 and proximal taperedportion 36 may also have different thicknesses, be made of differentmaterials, include one or more rigidity and/or flexibility features,and/or the like. In one embodiment, for example, proximal taperedportion 36 may be thicker than distal tapered portion 38, again topromote preferential collapse/invagination of distal tapered portion 38before any other portion of balloon 24. In one embodiment, for example,a thicker balloon wall of proximal tapered portion 36 may be achieved ina dipping manufacturing process by dipping proximal tapered portion 36more times than distal tapered portion 38. In another embodiment, whereballoon 24 is formed using a balloon blowing process, an additionallayer at proximal tapered portion 36 may be added after formation ofballoon 24. This layer may be a simple adhesive, additional balloonmaterial, or some other material that will bond to the blown balloonsurface. Additionally or alternatively, the blown balloon 24 may bepreferentially stretched to form a thinner distal tapered portion 38,thus creating the same or similar effective “strength differential” asmight be achieved via a thicker proximal tapered portion 36.

In yet another alternative embodiment, proximal tapered portion 36 mayinclude multiple rigidity features, such as longitudinally oriented ribs(not pictured). Such ribs may be formed, for example, during theblowing/dipping balloon formation process, by adding grooves in amandrel used to form balloon 24. Alternatively, ribs may be added afterballoon formation by applying axial lines of adhesive or other materialthat bond to the outer surface of balloon 24. Examples of such materialsmay include, but are not limited to, UV cure adhesive and polyurethane,nylon, and polyether block amide dissolved in a solvent solution.Alternatively, ribs made from polymer or metal strips may be bonded tooutside of balloon 24. Ribs may be made out of a variety of materialsand may provide additional proximal eversion resistance throughincreased thickness and/or by using a material of increased rigidity,stiffness and/or durometer.

FIG. 2A illustrates the fact that an optional feature of system 10 isone or more irrigation ports, apertures, openings or the like (notvisible in the drawing) for providing irrigation fluid 40 at or near thedistal end of system 10. Irrigation fluid 40 may serve the purpose, forexample, of helping clean the lens of camera 22, clear the field ofvision of camera 22, lubricate contact between system 10 and a ureteralwall and thus reduce friction during stone removal, and/or reduce painin the case where lidocaine or some other anesthetic is infused into thesite. In various embodiments, for example, fluid 40 may exit out of adistal end of system 10 via one or more small apertures in balloon 24(for example laser-drilled holes that allow fluid to slowly weep out ofballoon 24), via an irrigation lumen formed as a space between the innershaft and the retention member shaft, between camera 22 and the innershaft, or between the inner shaft and wall protection member shaft 42,or any other suitable fluid lumen or aperture(s). It may beadvantageous, for example, to provide irrigation fluid close to thedistal end of the camera, for clearing the field of view of the camera.This may be achieved, in some embodiments, by passing irrigation fluidthrough a space between the inner shaft and the retention member shaft.

Typically, only a low pressure of less than 1 atm is used to inflateballoon 24. This low pressure inflation enhances the ability of balloon24 to invaginate and in some embodiments to be advanced around theobstruction. Lower pressures are also advantageous in preventingureteral trauma associated with higher pressure and/or balloondiameters.

Once the obstruction is enveloped, it may often be easiest to remove theobstruction with balloon 24 partially or entirely deflated. In oneembodiment, using the constant force of a passive syringe, coupled withremoval system 10 and balloon 24 (via balloon inflation port 26), it ispossible to allow balloon 24 to deflate automatically due to the forceplaced on balloon 24 when basket 20 and stone S are pulled back intoballoon 24. In other words, the force and volume of basket 20 and stoneS being pulled into balloon 24 reduces the capacity of balloon 24 tohold fluid volume, which in turn pushes the fluid back up the ballooninflation lumen toward balloon fill port 26 and an attached syringe (orother fluid infusion source). In the case where the infusion source is asyringe, this fluid pressure will be sufficient to push an unobstructedsyringe plunger back, allowing balloon 24 to passively deflate. Otherconfigurations employing stop valves and/or pressure monitoring are alsopossible, in alternative embodiments.

In some embodiments, to aid in detection, it may be beneficial to expandthe ureter between the obstruction and the removal device. Inparticular, if the ureter is collapsed, then expanding it allows forbetter visualization. In the ureter, for example, about 1-2 cc of fluidcan often provide a small amount of passive dilation (about 1-3 mm in anaturally closed orifice), which allows greater obstructionvisualization. The dilation fluid used may be water, saline, or acombination of either with an analgesic agent. The fluid may beintroduced into the lumen/vessel in a variety of ways. For example, akidney stone removal device may emit a layer of fluid through relativelylow-flow rate nozzles to dilate the ureter (“hydrodilation”). In variousembodiments, for example, the flow rates used may be less than 20cc/min. This fluid buffer/hydrodilation may be used, for example, toprevent body luminal wall trauma during obstruction removal. A number ofnozzle profiles and hydrodilation techniques are described in patentapplication Ser. No. 13/761,001, which was previously incorporated byreference. The infused liquid (or liquids) may include water, saline,lidocaine and/or other suitable liquid(s).

Additional dilation may also be achieved through small perforations inballoon 24, in some embodiments. Perforations on the order of 0.006″ orsmaller provide adequate dilation without necessarily flooding the lumenwith fluid. In the case of the ureter, this implies minimizing renalpressure. Additionally, small perforations combined with a compliantballoon material allow for the perforations to effectively “seal” underlower pressures, allowing balloon 24 to inflate to a relatively lowpressure without liquid leakage. As the pressure is increased, theballoon diameter and fluid pressure increase, allowing liquid to passthrough the perforations and into the surrounding ureter or othervessel. This configuration may be advantageous for several reasons.First, it may help prevent over-inflation of balloon 24, by acting as apressure release mechanism. Second, the released fluid may act as alubricant, which will further facilitate stone removal. Third, theapertures may facilitate invagination of balloon 24.

A similar perforated design could be used in a non-compliant surfacewith smaller perforations. In this case, the increased water pressurealone would force the liquid from the non compliant structure. In suchembodiments, portions of the device on which it may be advantageous toadd perforations include the instrument shaft, grasper shaft, or innerlumen side-wall, among others.

In various alternative embodiments, a smaller amount and/or flow rate offluid may be introduced, for example to enhance visualization. This typeof fluid introduction/irrigation may provide some amount of passive orslight dilation of the ureter but is not typically designed to providehydrodilation.

With reference now to FIGS. 3A and 3B, one embodiment of system 10 isillustrated in side cross section and end-on cross section,respectively. Number labels for the components of system 10 are carriedover to FIGS. 3A and 3B from those prior figures. Furthermore, neitherFIGS. 3A and 3B nor any prior or subsequent figures are necessarilydrawn to scale. Referring again to FIGS. 3A and 3B, and moving fromoutside to inside, system 10 first includes outer shaft 16, which isattached at its distal end to proximal attachment portion 35 of balloon24, and wall protection member shaft 42 (or “balloon shaft”), which isattached at its distal end to distal attachment portion 39 of balloon24. Moving inward, the next component is an inner shaft 44, which hasbeen referred to above but is not visible on previous figures. The nextshaft moving inward is a retention member shaft 46, which extendsdistally into basket 20. As discussed above, retention member shaft 46and basket 20 (or “stone retention portion”) may be referred to hereingenerally as a “stone retention member.” In some embodiments, such asthe one illustrated in FIGS. 3A and 3B, the stone retention member isone piece, with retention member shaft 46 extending from a proximal endof system 10 to basket 20 at its distal end. In other embodiments, aseparate retention member shaft piece may be attached to a separatestone retention portion piece to form the stone retention member.

Camera 22 is housed coaxially within retention member shaft 46, so thatits distal end faces into basket 20. In at least one embodiment, camera22 and inner shaft 44 are both fixed to handle 12, such that the distalend of camera 22 is positioned at or near the distal end of inner shaft.Retention member shaft 46, in this embodiment, is free to slideproximally and distally over camera 22 and within inner shaft 44. Thisallows basket 20 to be advanced out of, and pulled back into, innershaft 44, while keeping camera 22 in a fixed position, thus reducingwear and tear on camera 22.

Some of the components of system 10 are movable, relative to othercomponents. One embodiment is described here, but this is only one of anumber of potential embodiments. In alternative embodiments, movement ofcomponents may be entirely or partially changed, without departing fromthe scope of the invention. In one embodiment, outer shaft 16 may befixed to handle extension 14 and thus may slide back and forth relativeto handle 12 as handle extension 14 slides back and forth. Wallprotection member shaft 42 may be attached to a slider on handle 12 orhandle extension 14. In some embodiments, wall protection member shaft42 may tightly contact the inner wall of outer shaft 16 and may simplymove in conjunction with outer shaft 16 via friction force and/or mayslide proximally when the stone and basket 20 are pulled into balloon24. As mentioned above, inner shaft 44 may be fixedly coupled withhandle 12, so that it does not move relative to handle 12. Finally,retention member shaft 46 (or “basket shaft”) may be coupled proximallywith slider 32 on handle 12, so that retention member shaft 46 may beadvanced to advance basket 20 out of inner shaft 44. Inner shaft 44, inturn, may be exposed out of the distal end of outer shaft 16 by pullingback on handle extension 14 to pull outer shaft 16 proximally relativeto inner shaft 44. In one embodiment, system 10 may be advanced throughthe ureter with inner shaft 44 extended out of the distal end of outershaft 16. Alternatively, outer shaft 16 may be retracted later in theprocess, for example when system is already advanced to a treatmentlocation, to expose inner shaft 44. Either way, the entire system 10 maythen be advanced, once inner shaft 44 is extended out of outer shaft 16,to pass the distal end of inner shaft 44 around and past the stone.Basket shaft 46 may then be advanced to expose basket out of the distalend of inner shaft 44. The whole system 10 may then be retracted to trapthe stone in basket 20. Camera 22, meanwhile, may be fixedly, thoughremovably, coupled with handle 12, so that it remains in a fixedposition relative to the moving components during the process. These andother steps of one method embodiment will be described in further detailbelow.

A mentioned previously, wall protection member shaft 42 may be mobilerelative to outer shaft 16. For example, it may be possible to retractwall protection member shaft 42 as basket 20 and stone are pulled backinto balloon 24. Alternatively or additionally, wall protection membershaft 42 may passively move back as basket 20 and stone are pulled intoballoon 24. Moving at least some of the components of system 10 relativeto other components allows kidney stone removal (or other obstructionremoval from other body lumens) using the method briefly described aboveand described in more detail below. The various components may be madeof any suitable materials, such as flexible polymers.

As mentioned above, this combination of moving parts of system 10 may bealtered in alternative embodiments. For example, it may be possible inone embodiment to fix outer shaft 16 to handle 12 and have inner shaft44 slide in and out of outer shaft 16. This is just one potential changethat might be made, and the embodiment described here is simply toprovide an example.

FIGS. 4A-4E illustrate one embodiment of a method for using system 10 toremove a kidney stone from a ureter (or other obstructions from otherlumens, in alternative embodiments). FIGS. 4A-4E are not drawn to scale.First, as illustrated in FIG. 4A, the distal end of the kidney stoneremoval system 10, here shown as outer shaft 16 and balloon 24, isadvanced into a ureter U to a position near a kidney stone S, just belowthe obstruction. Shaft 16 and balloon 24 may be advanced through anysuitable endoscope device, steerable shaft, catheter or other introducerdevice, such as but not limited to a cystoscope (not shown). In someembodiments, camera 22 may be used to visualize/detect the kidney stoneS and monitor advancement of system 10 to a desired location in theureter U relative to the stone S. Next, as illustrated in FIG. 4B,balloon 24 may be inflated, which may help maintain a position of shaft16 in the ureter U. Then, inner shaft 44, containing basket 20,retention member shaft 46 and camera 22, is advanced past the stone S.Camera 22 may be used to visualize this advancement as well.

As shown in FIG. 4C, basket 20 may next be advanced out of inner shaft44, allowing basket 20 to expand. Again, camera 22 may be used tovisualize advancement and expansion of basket 20. Next, as illustratedin FIG. 4D, basket 20 may be drawn back proximally (retracted towardouter shaft 16) to capture the stone S by retracting the entire system10. This step may also be visualized using camera 22. Finally, asillustrated in FIG. 4E, the stone S and basket 20 may be pulled backinto balloon 24, by pulling retention member shaft 46 proximally, thuscausing balloon 24 to invaginate and at least partially surround thestone S. Balloon 24 will help prevent damage to the wall of the ureteras the stone S is removed, by enveloping the sharp edges of the stone Sand thus providing a low-friction surface. The stone S may then beremoved by pulling shaft 16 and balloon 24 out of the ureter. Due to thelocation of camera 22 at or near the distal end of inner shaft 44, anyor all of these steps may be visualized via camera 22.

One optional step may involve dilating one or more areas of the ureterby inflating balloon 24 at any point during the stone capture and/orstone removal process. This may be useful, for example, if the system 10is being removed from the ureter and a constricted or narrowed area isencountered. In one embodiment, balloon 24 may be inflated to dilate atsuch an area, and then the inflation device, such as a syringe, may beused to actively deflate balloon 24 partially, or alternatively it maysimply be allowed to automatically retract to deflate balloon 24 to anominal pressure for continued removal of system 10 from the ureter.

In some embodiments, handle 12 may include a coupler for coupling camera22 with inner shaft 44, so that camera 22 is always located at the tipof the inner shaft 44. This ensures full visualization, while preventinghaving camera 22 protrude beyond the distal end and thus risk beingdamaged. Some embodiments may also include a frictional fit of basket 20in inner shaft 44, such that basket motion will be coupled to camera 22and shaft 44 when not actively controlled by the user, thus eliminatingthe need to move two sliders at once, while de-coupling the two whenactive, independent basket control is required. Other unique features ofhandle 12 are the dual-slider configuration and overall handle shape,which allow single-handed actuation. Yet another feature is the ballooninversion/invagination that is caused by sliding retention member slider32 until the captured stone is pulled against the tip of wall protectionmember shaft 42. Further motion of basket slider 32 causes wallprotection member shaft 42 to slide proximally relative to thestationary outer shaft 16, which in turn causes balloon 24 toinvaginate/invert. This design eliminates the need for an additional“invagination slider.” In some embodiments, however, wall protectionmember shaft 42 will, in fact, be attached to a slider. In someembodiments, this slider may be used to return balloon 24 to itsoriginal pre-invagination shape. Such a slide may also be used, ofcourse, to invaginate balloon 24 if necessary.

With reference now to FIGS. 5A-5F, another embodiment of a method forremoving a kidney stone using system 10 is illustrated. In thisembodiment, as illustrated in FIG. 5A, the distal end of the kidneystone removal system 10 is advanced through a ureter U with inner shaft44 already extended out of the distal end of outer shaft 16 and withballoon 24 deflated. As illustrated in FIG. 5B, all of system 10 maythen be advanced further, to position a distal end of inner shaft 44past the stone S. Still, balloon 24 is in a deflated configuration. Asshown in FIG. 5C, basket 20 may next be advanced out of inner shaft 44,allowing basket 20 to expand. Next, as illustrated in FIG. 5D, basket 20may be drawn back proximally (retracted toward outer shaft 16), byretracting the entire system 10, to capture the stone S. At this point,as illustrated in FIG. 5E, balloon 24 may be inflated. Finally, as shownin FIG. 5F, basket 24 and stone S may be pulled back into balloon 24.

In some cases, this embodiment of the method may be simpler and/oreasier to perform than the embodiment described previously. As should beevident from these embodiment descriptions, however, any given methodembodiment may include any suitable number of steps and order of steps.Some steps may be eliminated and/or added in various alternativeembodiments, without departing from the scope of the invention.

With reference now to FIGS. 6A and 6B, in an alternative embodiment, akidney stone removal system 110 may include an end effector 118 that hasa compliant funnel 124 (or “obstruction shaft”), rather than a balloon,to provide protection for the ureteral wall. End effector 118 may alsoinclude an expandable basket 120, a camera 122 and one or moreirrigation ports for providing irrigation fluid 140. System 110 mayinclude an outer shaft 116 and some or all of the other componentsdescribed above in relation to other embodiments. Due to thesubstitution of funnel 124 for a balloon, however, the design of system110 may be somewhat simpler. For example, system would not include awall protection member shaft or a balloon inflation port. Funnel 124acts in the place of the balloon as a guard against ureter wall traumaduring stone removal. As such, funnel 124 may be made of any suitablepolymer or other material that helps reduce or minimize friction and/orthat can serve as a protective layer to reduce trauma from sharp edgesof kidney stones. As illustrated in FIG. 6B, basket 120 and stone S maybe drawn back proximally into funnel 124, just as in the embodiment withthe balloon, except that funnel 124 does not invaginate or invert.Camera 122 may be positioned at or near the distal end of funnel 124,for visualizing the removal procedure. In alternative embodiments,funnel 124 may be replaced with any other suitable protective,friction/trauma reducing device, such as a shaft, cup, sock, lubricatedsurface or the like. Optionally, system 110 may include additional portsor apertures, for example at or near the juncture of funnel 124 andshaft 116, for providing lubricating fluid to further facilitate stoneremoval.

Expandable basket 120 may have a shape that facilitates the expansion ofcompliant funnel 124 around the stone S and basket 120. As illustratedin FIG. 6A, in some embodiments, expandable basket 120 may have atapered shape from the portion that retains the stone S toward theconnection of basket 120 with the basket shaft (not shown). The taperedshape may help align and expand compliant funnel 124 around the kidneystone S or other obstruction. The expansion of basket 120 may also beused to expand compliant funnel 124 around the obstruction. Using basket120 to expand complaint funnel 124 makes funnel 124 a passive component,reducing overall complexity of system 110.

Prior to use, complaint funnel 124 often needs to be retained in such away that it does not catch or rub on either the working channel of theintroducing device (cystoscope or other endoscope, for example) or thewall of the body lumen during advancement. One solution would be toprovide system 110 with an outer shaft that can slide over funnel 124 toprevent it from expanding prior to capturing the obstruction. Due tospace constraints, however, it may be advantageous to eliminate anexternal shaft from the device assembly. One such solution is to invertfunnel 124 inside outer shaft 116 around basket 120 during advancementto the obstruction. When basket 120 is advanced out of the mainassembly, funnel 124 is deployed into position (as in FIG. 6A). Avariety of variations to this deployment method using other aspects ofcatheter assembly (camera lumen or fluid introduction lumen, forexample) may be possible and will all function in an essentiallyequivalent manner to the above embodiment.

The embodiments thus far have involved systems in which expandablebaskets are used to trap a stone and pull it back into a protectiveelement, such as a balloon or compliant funnel. A different group ofembodiments eliminates the expandable basket and instead traps the stoneor other obstruction from the side of approach of the device toward thestone. For example, these embodiments typically involve expandablegraspers or expandable funnels that are advanced directly over/aroundthe stone and thus used to pull the stone out of the ureter. Some ofthese embodiments may also involve the use of suction to help pull thestone into the grasper. Several examples of such embodiments aredescribed further below.

With reference now to FIGS. 7A and 7B, one example of an expandablegrasper 210 that may be used to retain a stone or obstruction mayinclude multiple struts 213, each having a hooked distal tip 214. Asillustrated in FIG. 7A, the struts 213 are typically joined together ata proximal end 215. (FIG. 7B is a close-up view of several struts 213and distal tips 214.) Expanding grasper 210 may include any suitablenumber of struts 213, and struts 213 may include any of a number ofdifferently shaped distal tips 214, according to various alternativeembodiments. In some embodiments, distal tips 214 of struts 213 ofexpandable grasper 210 may be folded inward to form hooks or “teeth,” tohelp retain the kidney stone within grasper 210. Typically, although notnecessarily, grasper 210 will be combined with some form of protectivecoating, membrane, balloon or other protective component to reduce orminimize trauma to the ureteral wall during stone removal. When grasper210 is advanced out of a shaft in which it is housed, it will expand toa diameter sufficient to grasp a kidney stone. When grasper 210 is thenat least partially retracted (drawn back) into the shaft, grasper 210will contract at least slightly to grasp and hold the kidney stone.

In some embodiments, expanding grasper 210 may be configured to expandautomatically when released from a shaft. In such embodiments, forexample, expanding grasper 210 may be made by shape setting Nitinol orpre-bending an elastic material such as spring steel of PEEK into thedesired expanded geometry. The geometry can then be elasticallycompressed into a much smaller (unexpanded) shape within the shaft (forexample, catheter shaft having a diameter of 6 French or smaller).Expanding grasper 210 may be deployed by advancing grasper 210 out ofthe shaft and/or sliding the shaft back from the grasper 210. Bothresult in less constraint on the grasper 210, causing struts 213 tospread apart at their distal ends, thus increasing the diameter of thedistal end of grasper 210.

Referring to FIGS. 8A and 8B, another alternative embodiment of a stoneremoval device 220 may include an outer shaft 216, an expandable grasper226, with multiple struts and curved distal tips 228, and a protectivemembrane 224 positioned around grasper 226. FIG. 8B shows device 220 inplace within a ureter U and partially surrounding a kidney stone S. Invarious embodiments, membrane 224 may be made of any suitable polymer orother flexible material and may be configured to prevent trauma to aninner wall of the ureter U once the kidney stone S is captured therein.In various embodiments, membrane 224 may be one layer of material,multiple layers of material, an inflatable balloon, a funnel, a cup, asock or the like. In some embodiments, grasper 226 and membrane 224 maybe housed within outer shaft 216 during advancement of device 220through the ureter, and then advanced out of the end of outer shaft 216to expand and then trap a kidney stone S. In some embodiments, and withreference to FIG. 7B, grasper 226 and membrane 224 may expand until theymatch or slightly exceed the horizontal diameter of the kidney stone Sto be removed. In some embodiments, grasper 226 may be advanced out ofouter shaft 216 by an amount that achieves a desired diameter.

FIG. 8B illustrates part of a method for removing a kidney stone S froma ureter U, using removal system 220. As illustrated here, system 220 isadvanced to a location in the ureter U adjacent the stone S. Expandablegrasper 226 is then advanced out of outer shaft 216 (and/or outer shaft216 may be retracted back from grasper 226), to allow grasper 226 toexpand to its expanded, default configuration, such that distal tips 228are configured in a diameter as wide or wider than the stone S. Grasper226 may then be advanced over the stone S, thus capturing the stone S ingrasper 226. Protective membrane 224 acts to protect the inner wall ofthe ureter U while removal system 220 is used to pull the stone S out ofthe ureter U.

In some embodiments, a kidney stone removal system may include, or maybe used in a system including, a mechanism for dilating the ureter. Forexample, in one embodiment, a stone removal system may include a balloonthat encases grasper 210 or 226. The balloon may be infused with air,water, saline, a biocompatible lubricant, a local anesthetic (such aslidocaine), any other suitable substance, or a combination of any ofthese substances, to achieve a desired viscosity, cost, and/orperformance. The balloon may provide a smooth surface around theobstruction, reducing removal friction and facilitating passage. Inaddition, the balloon can be integrated in such a way that inflationcauses an additional retention force on the obstruction by inflating theside of the balloon on the inside of struts around the stone.

In alternative embodiments, dilation of the ureter (or other body lumenin other embodiments) may be performed via hydrodilation, without theuse of a balloon. Numerous embodiments of devices and methods forhydrodilation of body lumens, such as the ureters, are described inpending U.S. patent application Ser. No. 13/716,001 (Pub No.2013/0165944), entitled “Apparatus, Systems, and Methods for RemovingObstructions in the Urinary Tract,” the full disclosure of which ishereby incorporated by reference herein. Many of the embodimentsdescribed in the above-reference patent application use jets to propelfluid against the wall of the ureter to provide hydrodilation. Theseembodiments may be combined with the embodiments described herein, suchthat the hydrodilation jets may be used to dilate up and around a kidneystone from the proximal end (or “base”) of an expandable grasper, forexample. Alternatively, in one embodiment, hydrodilation may be achievedby ejecting fluid out of hollow tines of an expandable grasper (notillustrated)—i.e., using hollow grasping members as water channels withholes near the tips for water ejection.

Referring to FIG. 9, in another alternative embodiment, a kidney stoneremoval device 230 may include an expandable grasper having multiplestruts 234 with hooked distal tips 238, a dilation balloon 232 coupledwith struts 234, and a shaft 236 for containing the grasper and balloon234 during delivery into the ureter. Dilation balloon 232 may includemultiple apertures 240 (or “holes” or “perforations”) to allow fluid 242to pass from balloon 232 into the region around the obstruction. Forexample, a local anesthetic may be used to numb the region around theobstruction, a lubricant may be desired for further reduction offriction around the stone, and/or any of the fluids mentioned above maybe used to provide hydro-dilation force around balloon 232 to reducefriction and/or tissue trauma.

In the embodiment illustrated in FIG. 9, balloon 232 is positioned onremoval device 230 on the outside of struts 234. Balloon 232 may beinfused with air, water, saline, a biocompatible lubricant, a localanesthetic (such as lidocaine), any other suitable substance and/or acombination of substances. Attaching balloon 232 to the outside surfaceof struts 234 allows struts 234 to have hooks 238 (or teeth, etc.) toincrease the retention force on the stone, without risk of balloonperforation.

Referring now to FIG. 10, as mentioned above, any of the embodiments ofobstruction removal devices described herein may include, or may be usedwith a system that includes, one or more obstruction detectioncomponents. These obstruction detection components may be specificallyconfigured for kidney stone detection in some embodiments. FIG. 10illustrates another embodiment of a kidney stone removal device 250,including an expandable grasper having multiple struts 254 with hookeddistal tips 258, a compliant membrane 252 coupled with struts 254, onehollow strut 262, a small camera 260 extending through the lumen ofhollow strut 262, and a shaft 256, which the other components areadvanced out of and refracted back into. In one embodiment, for example,hollow strut 262 may have a lumen with an inner diameter of about 0.4mm. This lumen is large enough for a small fiber camera 260 to visualizea kidney stone directly. Illumination for small fiber camera 260 may beprovided, in some embodiments, around the sides of camera 260.Alternatively, illumination may be provided via a light source, such asa fiber, directed through a central lumen of shaft 256. In variousalternative embodiments, fiber camera 260 may be either reusable ordisposable. In other alternative embodiments, an inductance coil orimpedance sensor may be included for detection purposes, for example foruse in smaller lumens.

Referring now to FIGS. 11A and 11B, in another embodiment, a kidneystone removal device 270 may include an expandable mesh grasper 272,positioned inside an inflatable balloon 274 (or alternatively a membraneor other friction reducing/protective member), and a shaft 276 forhousing both. In one embodiment, expandable mesh grasper 272 may be madeof a shape-memory material and may have a configuration similar to thatof a vascular stent. Grasper 272 may be constructed from a number ofhighly compliant materials, such as Nitinol, spring stainless steel, orPEEK plastic, among others. The geometry can then be elasticallycompressed into a much smaller (unexpanded) shape within shaft 276 (forexample, a 6 French catheter shaft). Grasper 272 may then be deployed byadvancing grasper 272 out of shaft 276 and/or sliding shaft 276 backfrom the grasper 272. Either of these methods results in reducedconstraint on the expandable member 272, causing the tip diameter toincrease. This diameter can then be expanded until it matches thehorizontal diameter of the stone. In some embodiments, the tips ofexpandable grasper 272 may be turned/folded inward to form “teeth” tohelp retain the stone, similar to the hooks/teeth described above. Asmentioned above, in various alternative embodiments, expandable grasper272 may be combined with any other suitable protective member in placeof balloon 274.

Referring to FIG. 11B, in some embodiments, balloon 274 may be infusedwith air, water, saline, a biocompatible lubricant, or a localanesthetic (such as lidocaine). A combination of any of the above mayalso be used to achieve a desired viscosity, cost, clinical performance,functional performance, and/or the like. Balloon 274 creates a smoothsurface around the obstruction, reducing removal friction andfacilitating passage. In addition, balloon 274 may be integrated in sucha way that inflation causes an additional retention force on the stonebuy inflating the side of balloon 274 on the inside of mesh grasper 272around the stone. As described above in relation to other embodiments,balloon 274 may also include apertures or perforations to allow fluid topass from balloon 274 into the region around the obstruction. Forexample, a local anesthetic may be used to numb the region around theobstruction, a lubricant may be desired to reduce the friction of theobstruction on the surrounding wall, or any of a number of fluids may beused to provide a hydrodilation force around balloon 274 to reducefriction and/or tissue trauma.

As illustrated in FIG. 11B, in some embodiments, balloon 274 may bepositioned on the outside surface of mesh grasper 272. Having theballoon attached solely to the outside surface of balloon 274 allowsgrasper 272 to have “teeth” to increase the retention force on the stonewithout risk of balloon perforation.

Referring now to FIG. 12, in another alternative embodiment, a stoneremoval device may include an expandable mesh grasper 280 that includesa mesh 282 and webbing 284 disposed between or over mesh 282. Webbing284 may comprise a highly complaint material, which may be applied tomesh 282 via a dipping process, for example, thus forming a smoothsurface for the natural dilation created by grasper 280, and thusreducing the friction required for obstruction removal. In oneembodiment, a hydrodilation fluid may be emitted from a portion ofwebbing 284. Alternatively, hydrodilation fluid may be provided usingany of the methods described above. In one embodiment, webbing 284 mayserve as the protective element, eliminating the need for an additionalelement, such as a balloon, funnel-shaped membrane or the like.

Referring now to FIGS. 13A and 13B, a distal portion of anotheralternative embodiment of a kidney stone removal device 290, including aprotective balloon 292 is illustrated. Device 290 may include balloon292, an outer shaft 298, and an inner shaft 296 that moves in and out ofshaft 298. Balloon 292 may include a distal tapered portion 293 and aninner, stone entrapment space 294. When inner shaft 296 is fullyadvanced, stone entrapment space 294 is rolled outwards and becomestapered portion 293 (as in FIG. 13A). When inner shaft 296 is pulledback/retracted proximally, back into outer shaft 298, tapered portion293 rolls inward (or “invaginates”) to form stone entrapment space 294.

In one embodiment, a method for using device 290 may involve advancingthe distal end of device 290 into the ureter to a position near a kidneystone. Balloon 292 may then be partially inflated and then advancedaround the obstruction from the direction of approach of device 290,such that the kidney stone becomes trapped in entrapment space 294.Balloon 292 may then optionally be inflated further, using any suitableinflation medium provided via a central lumen or specified inflationlumen(s) of shaft 298. This method of approaching and capturing thekidney stone is advantageous, because it eliminates the complexity ofmanipulating the device past the obstruction. This embodiment of device290 may also reduce body lumen trauma and friction that results from thecatheter lumen placement adjacent to the stone. Balloon 292 (or othercomplaint material member in alternative embodiments) will typicallyhave a tapered shape and thickness configured to facilitate envelopingthe stone without necking or forcing the stone out of balloon 292 duringdeployment. In various embodiments, for example, balloon 292 may includea tapered portion at its distal end with an angle of between about 2degrees and about 45 degrees.

FIG. 13A shows device 290 with inner shaft 296 extended out of shaft 298to its maximum extent. FIG. 13B shows inner shaft 296 retracted to pullback on the distal end of balloon 292, thus forming entrapment space294. In some embodiments, balloon 292 may be rolled over a stone orother obstruction by retracting inner shaft 296 and advancing outershaft 298. Alternatively, it may be possible to achieve the same orsimilar effect by only retracting inner shaft 296 or only advancingouter shaft 298. Whichever method is used, entrapment space 294 may beformed to entrap the kidney stone for removal.

With reference now to FIG. 14A, in an alternative embodiment, a kidneystone removal device 300 may include a balloon 302, an outer shaft 308,and an inner shaft 306 that moves in and out of shaft 308. Balloon 302may include an inner, stone entrapment space 304 and a distal, taperedportion 303. Inner shaft 306 may include a rigid, distal ring 307 orplatform, which connects shaft 306 to the inside edge of a slightlyinverted balloon 302. The outside of balloon 302, attached to movableinner shaft 306, can be extended around the kidney stone or otherobstruction. Ring 307 may be positioned to sit on the bottom of thestone/obstruction, and balloon 302 may be advanced around the stone toenclose the stone in entrapment space 304. Ring 307 may help prevent thebottom portion of the inverted balloon 302 from “necking down,” whichmay help facilitate obstruction entrapment by balloon 302. Thephenomenon of “necking down” refers to the narrowing of balloon 302 inthe area where it connects to shaft 66, which can be seen in FIG. 13B.

With reference now to FIG. 14B, an alternative embodiment of a stoneremoval device 300′ with a differently shaped ring 307′ is illustrated.In all other ways, device 300′ is the same as shown in FIG. 14A andincludes a balloon 302′ with a tapered portion 303′ and an inner space304′, an outer shaft 308′, and an inner shaft 306′ that moves in and outof shaft 308′. In this embodiment, ring 307′ may have an atraumaticconfiguration so that when inner shaft 306′ is fully advanced, ring 307′will not inadvertently damage other structures. In one embodiment, atapered complaint material could be attached to the tip of balloon 302′to increase the rigidity of the tip section relative to balloon 302′.This tapered section will provide additionally rigidity to the tip, andcan prevent balloon 302′ from necking down to a small diameter as it isdeployed over the obstruction, similar to the function of ring 307′ atits attachment with balloon 302′. This material may also serve as anatraumatic trip during catheter deployment, and may be superior in thecase of tapered balloon 302′, as it will conform to the balloon shape.

In any of the above-described embodiments, suction force may be used tohelp draw a kidney stone or other obstruction into the entrapment spacein the balloon. In some embodiments, suction force may be applied via acentral lumen in the inner shaft of the obstruction removal device, sothat the suction force is applied directly inside the entrapment spaceof the balloon.

It is possible to combine any of the above-described removal methods. Acombination of the above may be preferable in some embodiments,depending on the obstruction location, size, required retention forceand/or other factors.

In all the embodiments described above in relation to FIGS. 13A, 13B,14A and 14B, the retention member, namely the balloon, also acts as thewall protection member. The two-sided complaint material, which isdescribed above as a balloon but which may have other configurations inalternative embodiments, may be partially infused with air, water,saline, a biocompatible lubricant, or a local anesthetic (such aslidocaine) then rolled or linearly extended past the stone. In someembodiments, as mentioned above, the dilation balloon may be perforatedto allow at least some of the fluid to pass into the region around theobstruction. For example, a local anesthetic may be used to numb theregion around the obstruction, a lubricant may be desired to reduce thefriction of the obstruction on the surrounding wall, or the fluid may beused to provide a hydrodilation force around the balloon to reducefriction and/or tissue trauma.

Any of the embodiments described above in relation to FIGS. 13A, 13B,14A and 14B may also include some form of visualization component. Insome embodiments, for example, a visualization device may extend througha central lumen of the moveable inner shaft, thus providingvisualization into the entrapment space of the balloon. In a 6Fcatheter, a typical size deployed through the working channel of anendoscope, this inner lumen could be upwards of 1 mm (3F). This wouldallow both a light source and fiber camera to be deployed down thecentral lumen for visualization.

Although this invention has been disclosed in the context of certainembodiments and examples, the present invention extends beyond thespecifically disclosed embodiments to other alternative embodimentsand/or uses of the invention and modifications and equivalents thereof.Thus, the foregoing description should not be interpreted as limitingthe scope of the present invention as described by the following claims.

What is claimed is:
 1. A method for removing a kidney stone from aureter, the method comprising: advancing a distal end of an elongate,flexible kidney stone removal device into the ureter to a location nearthe kidney stone; exposing an expandable, stone retention portion of astone retention member out of a distal end of an inner shaft of thestone removal device, to allow the stone retention portion to expand;visualizing at least part of the stone retention member with a cameradisposed coaxially within a retention member shaft of the stoneretention member so that a distal end of the camera is located at ornear a distal end of the inner shaft; trapping the kidney stone in thestone retention portion of the stone retention member; surrounding atleast a portion of the stone retention member and the trapped kidneystone with a ureteral wall protection member disposed on the distal endof the kidney stone removal device, wherein a first end of the wallprotection member is attached to an outer shaft of the device and asecond end of the wall protection member is attached to a wallprotection member shaft disposed between the inner and outer shafts; andremoving the kidney stone removal device from the ureter while the stoneretention member and the kidney stone are at least partially surroundedby the wall protection member.
 2. A method as in claim 1, wherein thecamera is disposed in the stone retention member shaft such that adistal end of the camera is located at or near a distal end of the innershaft.
 3. A method as in claim 1, wherein the surrounding step comprisesmoving the stone retention portion and the trapped kidney stone into thewall protection member.
 4. A method as in claim 1, wherein the ureteralwall protection member comprises an inflatable balloon, the methodfurther comprising inflating the balloon.
 5. A method as in claim 4,wherein surrounding at least part of the stone retention member and thetrapped kidney stone invaginates the balloon.
 6. A method as in claim 5,wherein the surrounding step automatically partially deflates theballoon and thus causes a plunger of an inflation syringe used toinflate the balloon to retract.
 7. A method as in claim 4, wherein theballoon is inflated before the surrounding step.
 8. A method as in claim7, wherein the kidney stone removal device is advanced at least part ofthe way to the location with the inner shaft extended out of the outershaft and the wall protection member shaft of the device.
 9. A method asin claim 4, further comprising inflating the balloon at least oneadditional time during the step of removing the device from the ureterto dilate at least one of a stricture or a narrowing of the ureter. 10.A method as in claim 9, further comprising at least partially deflatingthe balloon at least one time during the step of removing the devicefrom the ureter.
 11. A method as in claim 1, further comprising passinga fluid comprising at least one of irrigation fluid, lubrication fluidor anesthetic out of the kidney stone removal device in an area near thekidney stone.
 12. A method as in claim 11, wherein passing the fluidcomprises passing the fluid through a space between two of the shafts ofthe device.
 13. A method as in claim 1, further comprising removing thecamera from the device after use.
 14. A method as in claim 1, furthercomprising, before exposing the stone retention portion, advancing thedevice so that the distal end of the inner shaft is located on anopposite side of the kidney stone from the outer shaft.
 15. A method asin claim 14, wherein trapping the stone comprises retracting the stoneremoval device to trap the stone in the stone retention portion of thestone retention member.
 16. A method as in claim 15, wherein thesurrounding step comprises moving the stone retention portion and thetrapped kidney stone into the wall protection member.
 17. A method as inclaim 1, further comprising visualizing at least one of the trapping,surrounding or removing steps, using the camera.